Interest in flame retardant chemicals steadily has increased over the past decade spurred in part by a recognition of the serious hazards fires pose to property and life. New and stricter fire safety standards are being proposed by both governmental and non-governmental sources. The National Fire Protection Association estimates that in 1970 more than 2.5 million fires caused 2.6 billion in direct property losses and another $7.8 billion in indirect losses. Nearly 2 million people are involved in fires each year, and of these about 75,000 are hospitalized. Fires associated with flammable fabrics alone are estimated to cause 200,000 to 300,000 injuries each year. Associated medical costs are staggering, running well into the hundreds of millions of dollars. In 1970 it is estimated that 12,200 people died as a result of fires.
Heretofore a variety of approaches have been proposed for attempting to deal with the fire hazard posed by flammable fibers, e.g. blends of cotton fibers with polyester fibers. Generally these approaches have involved the chemical or physical application of a protective coating upon the surface of otherwise flammable fibers usualy while in fabric form. It has been found however, that the protective coating may (a) impair the otherwise attractive properties of the fibers (e.g. render the same stiff and harsh), (b) pose a toxic hazard particularly to the skin, (c) lose its effectiveness upon laundering, or (d) be incompatible with other finishes such as durable press, water - and soil-repellent resins, and dyeing processes.
Additionally, various proposals have have been made for the preparation of fibers which chemically are different from those which have achieved widespread usage and which are formed from a polymeric material having non-burning characteristics. Such fibers (a) commonly are difficult to prepare, (b) are considerably more expensive than the fibers presently marketed on a large scale, and (c) often lack the aesthetic properties sought for widespread mareketability. For instance, modacrylics commonly exhibit poor thermal properties and are difficult to dye. Aromatic polyamides tend to be expensive, to exhibit poor uv stability, and when dyed to fade readily. Polybenzimidazoles tend to be expensive and to be available only in the natural gold or brown color.
When a flame inhibiting component has been incorporated within a common synthetic fiber (e.g. by copolymerization), usually there has been observed an undesirable change in the resulting polymer, such as a reduction of melting point, a reduction in crystallinity, or other changes which generally tend to diminish end use fiber properties. Also it has been proposed to physically blend a flame inhibiting component within a synthetic fiber such as by coextrusion from a melt blend or from a common solution. This requires careful choice of an effective inhibiting component if other desired properties of the resulting fiber, such as strength, hand, color, etc., are to be maintained at the desired levels. Particular difficulties have been encountered in the past when one has attempted to inhibit the flammability of common fiber blends which are formed from melting and non-melting components, e.g. polyester/cotton fiber blends.
It is an object of the present invention to provide an admixture of separate and distinct fibers which is non-burning when subjected to a standard flame.
It is an object of the present invention to provide an inproved process for imparting flame resistance characteristics to fibers which would normally be expected to burn when subjected to a standard flame.
It is an object of the present invention to provide a flame resistant fiber admixture having satisfactory textile properties.
It is an object of the present invention to provide a fiber blend having satisfactory textile properties and resistance to burning when subjected to flame in accordance with the ignition procedure of the Children's Sleepwear Test (i.e. DOC FF 3-71).
It is an object of the present invention to provide a flame resistant fiber admixture which includes a substantial quantity of fibers which normally would be expected to undergo burning when subjected to a standard flame.
It is an object of the present invention to provide an improved flame resistant fiber blend which includes a substantial proportion of ordinary polyester and cotton fibers.
It is an object of the present invention to provide an improved flame resistant fiber blend which resists melt dripping when subjected to a standard flame.
It is an object of the present invention to provide an improved process for imparting flame resistance to ordinary textile fibers without deterioration in the textile properties thereof, e.g. hand and aesthetic appeal.
It is an object of the present invention to provide an improved process for rendering a polyester/cotton fiber blend flame retardant.
It is an object of the present invention to provide an improved process for rendering wool fibers flame retardant.
These and other objects, as well as the scope, nature and utilization of the claimed process, will be apparent from the following description and appended claims.